Automatic mechanism for firearms.



L. MARTINEZ-SILVA. AUTOMATIC MECHANISM FOR FIREARMS.

APPLICATION FILED MAY 5|1914.

Patented July 10, 1917.

2 SHEETS-SHEETL H HHHHHHHHMHUHMMMNA L. MARTINEZ-SILVA.

AUTOMATIC MECHANISM FOR FIREARMS.

APPLICATION FILED MAY 5.1914.

1,233,096. I Patented J u1 10,i917.

2 SHEETS-SHEET 2- m! Si mmkfbvm LUIS MARTINEZ-SILVA, OF BOGOTA, COLOMBIA.

AUTOMATIC MECHANISM FOR FIREARMS.

Specification of Letters Patent.

Patented July 10, 191?.

Application filed May 5, 1914. Serial No. 836,406.

To all whom it may concern:

Be it known that I, LUIS MARTINEZ-SILVA, barrister, a citizen of the Republic of Colombia, and residing at Rue 14, No. 18, B0- gota, Republic of Colombia, have invented certain new and useful Improvements in Automatic Mechanisms for Firearms, of which the following is a specification.

Th object of the invention is an automatic mechanism for automatic fire arms of the kind in which one portion of the gases produced by the burning of the charge in the cartridge is introduced into the mechanism for the purpose of acting on the different members of same.

The mechanism about to be described is characterized essentially:

By the fact that it comprises two springs (onefor opening the breech and the other for closing same) which are compressed simultaneously by a single member acted upon by a piston which is operated by the gases.

By the fact that the opening spring cannot expand, for the purpose of opening the breech, until the ball has issued from the barrel;

By the fact that the gases which operate the'mechanism are drawn ofi, from the barrel, at a comparatively long distance from the breech;

By the'fact that all parts of the mechanism which are liable to foul can be cleaned by drawing out a single member, and with-" mechanism is maintained in the position.

corresponding to opening the breech, as soon as the shell of the last cart-ridge contained in the magazine has been ejected. This result is obtained by means of members which, in contradistinction to those existing in other systems, arestrongly made.

The simultaneous compression of the two springs presents two chief advantages: in

the first place it opposes to the high power ofthe gases, all the resistances of the mechanism at once, so that the gases encounter the maximum resistance which the mechanism is capable of offering, the result being to reduce the violence with which the members are displaced to a minimum. The other advantage consists in the fact that the openopened prematurelyan accident which might have serious consequences.

Th location of the gas intake at a distance enables the gases to enter the automatic mechanism with a minimum of residue, heat and force.

The simplicity of the operation necessary for cleaning all the partsof the mechanism which are liable to foul as the result of contact with the gases, enables the cleaning to be performed quickly and without risk of losing any of the pieces.

The aggregate formed by the two tubes containing the chief members of the mech anism should not be taken apart to fit it on the weapon, being capable of being withdrawn and replaced as a whole and with great facility. Moreover, since the parts contained in the tubes are not exposed to contact with either the gases or rain, it is not necessary for them to be taken apart, though this operation can be performed by simply unscrewing the tubes, which, on coming apart, reveal all the internalmembers.

By means of an automatic device which, on the one hand, reliably insures combination between the automatic mechanism and the breech mechanism in opening and closing the breech, and on the other makes these two independent of each other when the breech is closed, the marksman can, at will, open andclose the breech by hand, without affecting the movable members of the automatic mechanism. To change from automatic to non-automatic firing (consecutive or single shots) all that is necessary is for the marksman to close the gas intake, lead ing to the automatic mechanism, by acting on a single member.

' abling the working of the mechanism to be Finally, in consequence of the b reech be ing maintained in the open position when thelast cartridge in the magazine has been ejected, the marksman, being thus warned that the ammunition of the firearm is exhausted, can easily recharge the magazlne; and in order to close the breech, all that he has to do is simply to pull the breech bolt lever, whichis then automatically brought which Figure 1 represents, in elevation, a longitudinal section of the automatlc mechanism;

Fig. 2 a detail ofthe mechan1sm,'1n plan and on a lar er scale;

Figs. 3 an 4 are diagrammatlc views enunderstood;

Figs. 5, 6, 7 and 8 are cross sectlons, along the lines aa, 6-6, 0 0 and (l -d respectively of Fig. l, and vlewed from the front?" Fig. 9 is a perspective VlGW OlI the devlce controlling the gas cock;

Fi -10 is a view, on a larger scale, of the safety device which prevents the breech from being opened before the ball has left the weapon;

Figs. 11 and 12 show two constructional -modifications of one of the members of this device;

Fig. 12 shows another constructional modification of this device;

Figs. 13, 14, 15 and 16, 17 and 18 are diagrammatic views showing three constructional modifications of the gas p ston, in elevation and cross section respectively;

Fig. 19 is a view of the breech block, the right hand portion of which 1s supposedto have been removed, thus enabling the Internal members to be seen, these being shown in the open position;

' Fig. 20 is a similar'view, the members being in the closed position;

Fig. 21 is a constructional modlfication of the automatic assembling device;

Fig. 22 represents a cross sectlon along the line AB of Fig. 20;

Fig. 23 is a View ot the breech, the right hand portion being supposed to have been removed, in order to show the operating rod Fig. 24 is a view, in vertical section, of the lower front part of the breech block, on a larger scale;

Fig." 25 shows a cross section along the line C- D of Fig. 24; and

Fig. 26 is a horizontal section along the line EF.of Fig. 24.

The automatic mechanism consists of a cylinder 1, into which the gases coming from the barrel are conveyed through apassage penetrates into the cylinder, a notch 4, which allows the gases to pass through when the cock is in the positionindicated in 'Fig. 1 On the other hand, when the cock 3 is turned half way around by means of the handle 5, as shown in Figs. 5 and 9, the notch .4 takes up a diametrically opposite position, which corresponds to the gas passage being closed. A for 6, the stem of which engages in the body'of the cylinder 1, and the branches of which form springs, keeps the cock 3 fixed in one or other of these two positions. A

piston 7, formed of a solid rod, is housed in the cylinder 1.

Behind the cylinder 1 are two cylindrical tubes 8 and 9, screwed one into the other and in the same straight line. These tubes contain a rod 10, the thickened front end 11 of which serves as, an abutment for the opening spring 12, .thefsecond abutment of which is formed by a block 13 surrounding the rod 10, the rear end of which'rod is provided with a thread on to which a second block 14 is screwed, being maintained in" position by a locking nut if required. Finally, the closing spring 15 is housed between the block 14'and a plug 16 screwed nto the rear end of the tube 9. This plug 16 is secured by means of a screw 17, which also serves to keep in place a member 18 mounted on the left hand side of the tube 9, with which it engages, in the first place, by'rneans of a dovetail. This member takes the form and plays the part of a hook, the body of which is formed of a flem'ble blade.

Above the point at which the block 13 is situated when the mechanism is at rest, is located another passage 19, which enables a small portion of the gases to enter a chamber 20 provided with a piston 21 which carries a tooth 22 engaging in' a perforation provided in the bottom of a socket 23 which is screwed into a thickened part of the barrel. The tube 9 is cut away below the tooth 22, so as to enable said tooth to. drop into a means tube 9, a portion of which is shaped awaytween the lugs 13 and 14 of the blocks 13 and 14. Moreover, the rod is held and guided by the stock 27, which is fitted, for this purpose, with a thin strip of steel 28. The stock 27 is put in position by placing it against the under side of the mechanism, and is held there by means of a sling ring and band.

The automatic -mechanism acts in three stages, which succeed one Q another in the following manner: Preparatory stage or setting the mecham'sm.-Fig. 1 shows the mechanism in the position of repose. When, after firing the shot, the ball has passed the gas intake passage 19 in the barrel, a small portion of the gases forces the piston 21 downward and keeps it in contact with the bottom of the socket 23. At the same time the tooth 22, which is in one piece with the piston 21, is held in position in the notch 24 of the block 1 13, which is thus rendered immovable.

When the ball has passed the main gas i11 take passage 2, a portion of the gases forces the piston 7 backward. The piston 7 pushes the rod 10, and at' the same time compresses the opening spring 12 against the block 13, which is fixed, and the closing spring 15 against the plug 16. During this movement the lugs 14 and 14 of the block 14 slide in the longitudinal openings 9 and 9 and at the same time the lug 14 slidesin the recess in the rod 25. Toward the end of its stroke the lug 14 raises the hook 118 which, in consequence of its flexibility, drops down in front of this lug as soon as the latter has passed the tooth of the hook, so that the block 14, and consequently the rod 10, cannot return in the forward direction under the thrust of the two springs 12 and 15, which are therefore kept in the compressed condition. Fig. 3 shows the mechanism in this position.

It will be evident that if the ball remained in the barrel, between the passage 2 and the muzzle, the gas pressure would be maintained, and therefore the block 13 would remain immovable.

Opening-the-breech stage (release of the opening. spring 12) As soon aS the ball has issued from the barrel, the gases escape from this latter, the cylinder 1 and the chamber 20. Consequently, the tooth 22 is no longer held down in the notch 24, except by its own weight and that of the piston 21.

the closing spring 15.

Forced by the spring 12, which expands, the block 13 then raises the tooth, by reason of the inclined planes with which the tooth and the notch are provided, and pushes the rod 25 rearward by the aid of the lug 13, which bears against the rib 25. This is the opening-the-breech stage.

Fig. 4 shows the mechanism at the end of its opening stroke. i

' Glosing-the-breech stag (expansion of the closing spring 15 and return of all the members to their-initial position).When

the block 13 arrives at the end of its stroke,

its lug .13" raises the stop hook 18, which releases the lug 14 and consequently the block 14, which is then ushed forward by.

he lug 14 pushes the rod25 forward, by bearing against the rib 25' which came into contact with the 1 lug 14 at the end of the opening stroke. The rod 25 in turn brings all the breech members into the closing position, the weapon being cocked. The latter is then ready for firinganother cartridge, without the marksman having had to move the weapon from his shoulder. When the closing stage is com pleted, the members of the automatic mechanism occupy the position shown in Fig. 1, that is to say are at rest.

In moving forward again the block 14 and the rod 10 have drawn with them the block 13 and spring 12. Owing to the slight- The tooth 22 iskept bearing in the notch I 24 by a force which, for the sake of simplicity, may be assumed as equal to that which effects the simultaneous compression of the two springs 12 and 15. The spring 15, which is necessarily more powerful than the spring 12, absorbs about two-thirds of the force requlred for the simultaneous compression of the two springs, whence it follows, inversely, that the force of the opening spring 12 is less than one-third the force of the gases. Consequently, the tooth .22 is held by a force at least three times as great as that which the spring 12 tends to exert when compressed; but, in addition, the spring 12 must, in order to open the breech, overcome the resistances presented by the unlocking of the tenons of the breech bolt. These resistances are much greater during the course of the ball toward the muzzle of the barrel, owing to the pressure exerted by the gases on the head of the breech bolt. In these conditions it will be evident that the available force of the spring 12, diminished by these resistances, remams very small until the ball has issued from the barrel; and

this force is opposed, through the agency of the tooth 22, by the force of a portion of the gases, which force was sufficient to compress the two springs simultaneously.

Fig. 10 shows a tooth with a pomted t1p like a center punch: in Fig. 11 the end of the tooth is rounded: and finally in Fig. 12 the tooth is of square section, with wedge shaped tip. Other modifications of shape than those illustrated here as examples may easily be imagined, the essential point being to get the end of the tooth 22 to engage W1th the block 13 and, by means of the inclined planes or rounded shape, to enable this tooth to. be lifted vertically by the block, which moves in a direction at right angles thereto; v

The device shown in Fig. 12'--provided the head 21 of the piston comes flush with the interior of; the barrelpresents' the advantage of preventing any permanent deposit of residue. Hence, there is no need for. the device to be frequently cleaned.

In Fig. 1 the chief piston 7 is shown as though formed of a solid rod. Constructional modifications are illustrated in Figs. 13 to 18.

Figs. 13 and 1 1 show a piston the weight of which is reduced by the provision of longitudinal channels. I

Figs. 15 and 16 represent a piston of a shape which enables the gas, on arriving in front of the end of the piston, to enter,

first of all, into chambers or open spaces situated above, below or even at the sides. The pistonis then acted upon by thegases continuing to arrive through the passage 2, and, in proportion as the pistonrecedes in the cylinder 1, a counter-pressure, due to the gases partially surrounding the piston, is set up in the'cylinder, and the'force of impact of the gases against the piston is thus lessened. The piston might also be constructed in such a way as to leave only one chamber.

Figs. 17 arid 18 show a'piston, the front portion of which is hollowed out'for a certain distance, the rearward portion being solid. The object of this form is to insure a perfectly tight joint between the piston and the cylinder in which it travels, in consistance of the latter is considerably increased.

In order to clean out the cylinder 1, all that is needed is to unscrew the cock 3 completely, and then cause the-piston 7 to drop out by holding the Weapon vertically,'barrel downward.

To clean out the safety device .(piston 21) it ,is sufiicient-after having removed the stobk, and the tubes 8 and 9 (together) to unscrew the socket 23. The truncm conical shape of'the chamber 20 enables the piston 21 to expel any residues which may have been deposited on it, through the passage 19.

To remove the automatic mechanism as a whole,-the weapon must be tilted slightly toward the left, after having removed the stock, the cock 3 and the piston 7, Whereupon the tubes 8 and 9 drop out of their own accord.

These tubes are held, at the rear end, by a nipple forming part of the plug 16 and at the front end by the piston 7 which projects slightly beyond the cylinder 1.

. In Fig. 1 the handle of the bayonet carries a heel piece 30 which bears against the solid part connecting the barrel with the cylinder .1, so that the cock 3 can be operated even when the bayonet is fixed.

Connection between the automatic mechanism and the movable members of the breech block is established, through the operating rod 25, by means of the following device, shown on Figs. 19 to 22.

On theupper side and near its rear end, the operating rod 25 is provided with a lug 31, which bears against a-projection 32 ar ranged on the lower edge of the sleeve 33. Bythe aid of a slanting groove 34 provided in the sleeve 33, and in which the tenon 35 of the breech bolt 36 engages, the longitudi:

nal; rectilinear movements of the sleeve 33 effect the opening and closing ofthe breech,

position of repose, the hook 37 tends to drop, by its own weight and pivoting on thepoint 38, into a recess 39 provided in the horizontal part of the slide in which move the rod 25 and the lower portion of the sleeve 33, the rectilinear movement of which is insured by means of ribs 40 engaging in corresponding grooves in the breech casing.

Near to the pivotv 38 the hook 37 is providedwith a'claw 41 which, when the members are in the position of repose, abuts against a projection 42 in one, piece with the wall of the breech casing, so that the hook 37 is forcibly held embedded in the recess 39.

Under these conditions the marksman can at all times open and close the breech by working the operating lever 43, without moving the hook 37 and rod 25, and therefore without having to overcome the resistan'ce of the springs of the automatic mechan sm.

v The shocks to the weapon I the projection 42. At the beginning of this plete.

movement, the head of the hook .37 comes in contact with an inclined plane ,44 which compels the hook 37 to pivot and come in contact with the sleeve 33. When the members arejin the position shown in Fig. 20, and the hook 37 is in contact with the horizontal portion'of the slide, the engagement of the hook 37 and the sleeve 33 is com- The rod 25 continues its rearward course and then, under the influence of the automatic mechanism, returns in the forward direction to close the breech. It will be easily understood that, in returning in the forward direction, the rod 25 draws with it the sleeve 33, by means of the assembling hook 37, the tooth 45 of which is in engagement with thev projection 32. Owing to the resistance set up by the locking of the tenons of the breech bolt toward the end of the return stroke of the rod 25, the hook. 37 still remains engaged with the sleeve 33 by contact, although the weight of the hook 37 tends to cause it to drop when it arrives over the recess 39. For this purpose the sleeve must commence to lock the breech bolt before the hook 37 is completely engagedabove the recess 39. In the last few millimeters of the return stroke, the claw 41 strikes against the projection 42, which compels the'hook 37 to drop into the recess 39.

A constructional modification is shown in Fig. 21. The assembling member or cam 46 ishinged toward the rear on the end of the rod 25, which is necessarily longer than in the previous example. As in the case of the hook 37 a claw 41 and a projection 42,

insure the lowering of the cam 46 into a recess 39, the inclined surface 44 of which compels the cam 46 to come into engagement with the projection 32 on the sleeve 33.

It will be understood that the dimensions and proportions of the hook 37 or of the cam 46 may be varied according to the shape of the breech members.

The movable members of the breech and the automatic mechanism are automatically fixed in the position corresponding to the opening of the breech, (as soon as the. shell of the last cartridge contained in the magazine has been ejected), by means of the following device, which is shown in Figs. 23 to 26.

of which is threaded so as toserew into.

the breech casing, engages in a recess 47 provided in a forward extension of the breech casing 29, as shown in Fig. 24. An arm 50, in one piece with the pawl 48, serves as abutment for a weak. spring 51, the second abutment of which is formed by a screw 52, hollowed out to house same. This screw 52 also serves to retain a plate 53 dovetailed into a recess in the side of the breech casing and serving to close the mouth of the recess 47. An opening 54 places the recess 47 in communication with the slide in which moves the operating rod 25 of the automatic mechanism.

On the other hand, the cartridge carrier 56 is provided withva finger 55, which is .hinged on the cartridge carrier and penetrates into a groove 57 arranged in the bottom of the front end of the magazine. The left wall (Fig. 25) of the groove 57 is in the extension of the corresponding side of the magazine, in order that the points of the balls shall. not enter it. As can be seen from Fig. 25, the pawl 48 is of such a shape as to present, in front of the upper part of the groove 57, a surface 58 sloping at an angle of about 45 degrees. 1

At a suitable point the two parallel edges of the rod 25 are connected by a rib 59,

which exhibits an inclined surface 60 and a sharp edge. 61. The position of this rib 'is determined by the distance the rod 25 has to travel in order to open the breech, bearing in mind that this rib should come into position a little beyond the opening 54 when the breech is fully open.

The system operates in the following manner:

In proportion as the cartridge carrier ascends during the automatic firing of the cartridges contained in the magazine, the finger 55, being hinged, rises in the groove 57 and, when the last cartridge has been inserted into the barrel, the cartridge carrier assumes the position shown partly by. broken lines and partly by full lines, in Fig. 24. During the last stage of the ascent of the cartridge carrier, the finger 55'is 1n contact with the inclined plane 58. Owing to the force of the springs lifting the cartridge carrier, the finger 55, in'ascending, pushes the pawl 48 toward the right, by overpowering the force of the small opposing spring 51 which, up to now has kept the pawl in front of the groove 57. In plvoting finger through the opening 54 into the groove25" of the rod' 25..-When the last cartridge has been fired, the automatic mechanism comes into action and forces the about the point 49, the pawl 48 pushes its rod 25 to the rear to open the breech.

' the tooth of the pawl 48 which, as soon as The pawl and rod engage quietly, l

to hold the rod 25, inspite of the effort of the-return spring of the automatic mecha nism, the pawl 48 is provided at 62 with shoulders which produce this result by hearing against the corresponding parts of the breech block.

In order to effect the closing of the breech when the magazine is full, the marksman has merely to pull the operating lever 43 of the sleeve 33 backward for a short distance, which sleeve moves the rod 25, and,

' as the cartridge carrier is down in the hot- I of the spring 51.

tom of the magazine, as soon as the rib 59 is detached from the pawl, this latter returns to its initial position under the thrust The automatic mechanism is then ableto. draw forward the ro 25 and close the breech. a

If the marksman has to close the breech, leaving the magazine empty, he must first place a cartridge in the magazine, then pull the operating lever to effect the automatic closing of the breech and the insertion of the cartridge into the barrel. The sleeve 33 being detached automatically from the rod 25, in consequence of the automatic depression of the pawl 37 the marksman can then open the breech by hand and take out the cartridgeby withdrawing it from the extractor, after which he recloses the breech anduncocks the weapon as in an' ordinary It may be mentioned that none of the members composing this system projects outside the breech casing, and that, consequently, the marksman cannot suddenly stop or close the breech accidentally by touching the system inadvertently.

What I claim is:

1. In automatic small arms, in which the breech mechanism is actuated by the gases produced by the explosion of a cartridge, in which a part of the rod of the automatlc mechanism engages with the front of the movable member of the breech when the latter is in closed position, and when being opened by said automatic mechanism, a pivoted member carried by said 'rod, a hook like projection on said member adapted to.

engage with the movable member of the breech mechanism on' the opening of the breech and until it has been closed thereby,

' means on the breech casing for effecting the inoperative position.

2. In automatic small arms, in which the breech mechanism is actuated by the gases produced by the explosion of a cartridge, locking means, located entirely Within the body of the weapon, andindependent of the breech mechanism, adapted to co-act with a part of the automatic mechanism to prevent the closure of the breech after the last cartridge has been discharged in automatic firing, until the parts are disengaged by a slight backward movement of the sliding part of the breech, said locking means comprising a pawl located in a recess formed in the breech block, a spring for normally retaining such pawl within the recess, a lug,

formed on the cartridge lifting cartridge carrier, adapted to engage with and displace said pawl when the last cartridge has been inserted intothe barrel, and cause it to project into the path of a projection formed on a part of the automatic mechanism so that v the rod is engaged and held by the pawl the moment the breech is fully open.

In testimony whereof I aflix my signature,

in presence of two Witnesses.

LUIS MARTINEZ-SILVA.

Witnesses: I

RAOUL THOMAS, CHAS. P. PRESSLY. 

